定义:在平面直角坐标系中,过一点分别作坐标轴的垂线,若与坐标轴围成矩形的周长与面积在数量上相等,则这个点叫做和谐点.
(1)判断点M(﹣1,2),N(﹣4,﹣4)是否为和谐点,并说明理由;
(2)若和谐点P(a,3)在直线y=﹣x+b(b为常数)上,试求a,b的值.
根据句意及首字母提示补全所缺单词。(1)--Thank you very much! --You’re w____ (2)Do you w ____ a big bed or a small one for your son?(3)I get a school bag at a very good p____ (4)There is a big s____ near our school. There are many school things in it.(5)You can b____ some food in a supermarket (超市).
下列四个地区中,以白色人种为主,人口自然增长率最低的是( )